The energy debate surrounding Proof of Work (PoW) blockchains like Bitcoin and Ethereum is nothing new. While the world’s wealthiest man might have rekindled the flames with his sudden about-turn on Bitcoin, Elon Musk is hardly the first person to be concerned over the high amount of energy that Bitcoin mining and other similar POW chains require.
In fact, Tendermint co-founders and the authors of the Cosmos Network whitepaper, Jae Kwon and Ethan Buchman recognized this problem in 2014 when their research into Proof of Stake (PoS) and blockchain consensus mechanisms led them to develop Tendermint Core — the first and most widely used implementation of a Byzantine Fault Tolerance (BFT) consensus engine and PoS crypto-economics to date.

How Cosmos Proof of Stake Solves the Energy Issue
Cosmos solves the problem of high energy consumption by using a Proof of Stake consensus mechanism relying on our Tendermint Core engine that achieves high performance with a low carbon footprint. We also enable blockchains to scale and connect through our groundbreaking IBC protocol.
read the details here https://blog.cosmos.network/why-blockchains-need-cosmos-proof-of-stake-for-a-sustainable-environment-878b3edd2e85